This computer science lesson is the fourth in a series about cryptocurrency and non-fungible tokens, also known as NFTs. The series examines some of the technologies underlying various cryptocurrencies such as Bitcoin, as well as some the ethical, cultural and legal implications of these digital currencies. In this particular lesson you will learn about Bitcoin transactions and unspent transaction outputs, also known as UTXOs. You will see that a transaction has inputs, which refer to the outputs of previous transactions, and outputs which specify to whom a payment should be made. You will also be introduced to the concept of change in a transaction, which means there is no need for the Bitcoin network to maintain accounts or account balances for individual users. In this video you will learn that new bitcoin are created by miners, incentivised by the block reward and transaction fees. You will also learn about the purposed of the so called generation transaction, also known as a coinbase transaction.